Battery-charging system.



6. o 9 1 8 1 nu E D D E T N n A M P E T s .Y NS 0G S Mm 0G HR TA .H IG .Y WR B mi T A B PPLIUATIOI FILED AUG. 1904.

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(ivi/[memes Cc@ inganna NITED STATES PATENT OFFICE,

'ILLIAM I. THOMSON, OF .\`l-\YARK. NEW JERSEY, ASSIGNOR -TO THE SAFETY CAR H EATIXG & LIGHTING COMPANY.- OF XElV YORK, N. Y.,- A CORPORATION OF NE' J ERSEY.

BATTERY-CHAReiNG'sYsTeM.

VNo. 838,822.

Specication of Letters Patent..

Patented Dec. 18, 1906.

Anuman ma Angus 17. 1904. sei-n1 No. 221.01m.

To ali whom it concern:

Be it known that'I,4 WILLIAM AI. THOMSON, residingl at Newark, m the county of Essex and State of N ew Jersey, have invented certain new and useful Improvements in Battery-Char ind Systems, of which the followclear, and exact description, such as will enableI others skilled in theart to which it appertains to make and use the same.

This invention relates to generating systems particularly ada ted for use in charging secondary or storage atteries.

Certain features herei shoivn and described are shown, described, and claimed in my copending application, filed Julv 18, 1904, Serial No. 216,923, and accordingly are not herein claimed.

One ofthe objects of this invention is to provide simple and efficient apparatus wherey thecurrent used in char v a -stor Ue battery is automatically reduced upon t e battery becoming fully charged and 1s automaticallv increased upon the charge of the battery falling below a certain point.

' Another object is to provide means of the above type adapted for use in connection with a system of the nature of that described rin my copending application above referred to.

Other objects will be in art obvious and in art pointed out hereina ter.

`he invention accordingly consists in the features of construction, AcombinationsI of elements, arrangement of parts, and means for the utilization of principles which will be exex'L lified in the apparatus herein described and t e scp e of the a plication of which will be indica in the following claims.

In. the accom anying drawing is shown a diagrammatic p an of one of the various possible embodiments of my invention.

Preliminary to a descri tion -of this embodiment it may be noted t at altho Uh there `are certain advantages in the use o a constant-potential-generating system for charging storage batteries-such as, for example, the automatic cutting down of the How of current therethrou h as tho battery charge increases-nevert eless the use of a constant current system is for some reasons Lighlv de srable. Yith a system of the lastme'nti'oned type in general the available forces for use in regulation are greater than those in constant influences. Also in a constantcurrent reguv lation where the regulating apparatus is not cut in until the voltage of the generator equals that ofthe battery an increase of a certain amount' in the total generator-voltear! causes alarger proportional change in the current owmg from the4 enerator to the battery than in the totalvo tage of the gen erator. For example, if the batteryvoltage is one hundred, and ten amperes would How through the same with a Generator voltage of one hundred and live, the current flowing when the generator-voltage rises to one hundred and ten would be twenty amperes-a change in current of one hun red er cent. and a chanac in voltage of less t an five per cent. 'he principal ob'ection to constent-current charging is, as a ove indicated, the tendency to overcrliarge the battery, and it is true that althou h overchargi 0 iery bv means of iorcing a mili? current through the same is beneficial thereto, yet to the batwould in time ruin it. T e above and other objections are overcome in constructions of the nature of that herein described.

Referring nov. to the drawing, 1 represents a shunt-wound generator having serially connected within tne field 2 thereof a variableresistance medium 3 3, which may consist of vone or more series of carbon plates, the pressure with which these plates contact beimr ,varied, as hereinafter described. Connect to the generator 1, by means of conductor 4, is one terminal of a secondary cr'storage battel-y 5. It may here he not-ed that the terms secondary and storage. as descriptive of a battery are used in this description and throughout the following claims as synonymous and as having their ordinary meaning familiar 'to those skilled in the irrt. The remailling terminal of battery is connected by a conductor 6 to onepole of a double-pole switch 7, the other pole of which is connected by conductors 8 and 4 to the first-mentioned pole of the battery. The opposing contacts of double-switch 'iA are connected with the mains 9 and 10, between which are bridged lamps or other current-utiliznvr devices 11.

Leading from terminal4 12 ofD generator 1 is Molilli the coril, about. which this coil isi' wound, isunurnmture |8,p|votally mounted g of armature 1S a contaot-brush 21 mounted spectivelv, und are so arranged us to enga re 'tures IS und 25 are preferably pii-'otally -tor 37 und ninmeter 38 to the conductor 6.

upon nn arm It), whiol'iisseeured to the opposite end of rore i7 in any desired manner. Armature 1S is normally held in a retracted posit ion by menus of an adjustable spring 20; hui upon the force of this spring being overconn` by the attraction oi core 17 the armature is movedto a position adjacent thereto, in which the magnetic circuit. through coro 17, :mn 19, und armature 18 is much improved. By means of this lost-mentioned movement thereon is brought into engagement with contuetfblock 16, thus. -complet-ing the circuit from the latter to urnmture 1S. (.orbon blocks 22 und 123 are preferablyattached to contart-,bhaek I6 and contact-brush 2]-, re-

one nnot ier before .the engagement. of -t ic lnst-n|entioned members und to remain in engagement of ter these parts have separa ted, so as to prevent burning ol' the contact-surfaces thereof.

Leading` from armature 18 isa conductor '24, which ma kes connection withan armature :25, pivotally mounted upon the ironie 26 of on electroniegnetie. switch, which embodies some of ,the more important features of my invention. Mounted upon frame .26 is n core 2, about which is wound a conductor 28, which is connected to the generator )at terminal 12 and passes through the remaining winding 2f) of the previously described switch J5. From the winding about the core 27 conductor '2S is carried to generator-termi-. nal 30, as shown in the drawing. The coils in this circuit ure preferably of line wire und many turns, so as to he controlled substatitially by the voltage of the generator. Arma.-

lnonnled substantially at. their renters of gra vit y, sous to reduce .he efl'ect of jars and x-'ihriitions thereon, and the latter is normally held in n retracted posit-ion by means of on adjustable. s )ring 31. In this position the contact-bluish 32, borne by the armature, is in electrical engagementwith a contactblock 33, which is mounted upon and insulated from the frame 26. Contactdirnsh 32 and contact-block 33 are preferahl) provided `with carbon blocks .34 and 35, respectively, which are. similar in character and identit-al in function with the corresponding ports in the previously-described ,switch 15. W'ith contact-brush 32 in engagement with its courting eontnctfbloek the circuit is completed from orma ture 25 through these parts to a resistance-roi! 36 and thence through conduc- A 'shunt-cirouit is completed from the'framo 2G through 'a ,Solenoid 39 to the conductor 37,

and claimed in` my eopending applit-ation above referred to, it may be noted vthat by ineens of solenoid 39 the core 4t) is controlled su as tovert the pressure upon the groups of carbon blocks or disks 3 by means of a yoke 43 in accordance with the amount of current flowing through this coil. As this ressure is varied the tot-al resistance of i -ihle-resistunce medium 3, 'and consequently that of the field-circuit in which it is connected, as above described, is correspondingly varied' and the field of the generator consequently made more strong or weak, according as the current through this coil is diminished or increased. In this manner the current through solenoid 39 1s maintained substantially constant.

Fuses 44 are preferably disposed as -indicated in the drawing to accomplish .their ordinary functions and, -if necessary, may be duplica ;ed at any other desired pointsof the system.

The operation of the above-described em.4

hodiment of my invention is as follows: .Vith the parts in normal position let it be assumed that the generator is started. The entire outputof the generator is directed through conductor 13, coil 29, and conductor 28, no current flowing in the solenoid 39, thus enabling sprintr 41 to ronipress the variable-resistance. medium 3 and reduce the total resistnncc Yof the field of the generator, enabling itniore. quickl to build up. Spring 20 is adjusted so as to permit armature 18 to be attracted hy core 17. and thus close the oire-uit between contact-brush 21 and contactbloolr 16 when the voltage of the generator4 hns become equal to that of the battery. A circuit is now complete from the generator through winding 14, contact-block 16, contact-brush-ZL and conductor .24 to ermature 25. From this point two paths are open to the current, one leading through contactbrush 32 and contacbblock 33, which aro normally held in engagement by means of spring 31, resistance-coil 36, conductor 37, conductor 6, and battery, thence to terminal 30 of the generator. The. other path leads through the frame 26 of the switch-coil of solenoid 39 and leads to the conductor 37 ,and thence tn terminal 30, as above described. Resistance-coil 36 is preferabl so proportioned in resistance to that of coi 39 as to cause. the greater portion of the current to flow through the former. -'it-h .the parts in this condition the current is maintained Substantially constant b means of solenoid 39- aetng upon the variable esistanco. me-

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'above construction dium 3, and the batteries are charged at a substantially constant rate. The parts are so arranged and adjusted that upon the battory being charged to its full extent--as,`for example, two and one-half volts per cellthe 'current passing through coil will cause the attraction of armature 25, and thus open the circuit through resistance-coil Jb between contact-brush 32 and contactblock 33. The 4cul-)ut of the generator is thus directed entirely through coil 39, and the lield thereof istemporarily made much stronger, thus attractin core and correspondingly increasing t ie resistance of resistance medium 3, so as to weaken the field of the generator and reduce the current flowing in Athis coil to its normal amount. The current passi through the battery may thus be red ucc to any desired fraction of the full current and fluctuation thereof prevented by means of the re latin(1 device, as above described. It wi l be o vious that uponthe generator-voltage being reduced, as a ove set forth, below the value at which armature 25 was attracted this momber'will not necessarily fall away from the core, with a consequentv oscillation upon the voltage be-v ing alternately raised and lowered, as by virtue of the armature coming into closer proximity to the attracting-core it will be held in position with a much weaker field vthan was originally required to attract-it. Other factors, such as the friction and inertia of the moving parts in conjunction with the above change of position of the armature, absolutely do away with any tendency to oscillation of this art.

It will thus be seen that I have provided simple and elicient apparatus whereby constant-currentenerating apparatus with all its inherent a vantages ma be safely and economically used for charging storage batteries. The apparatus required to accomplish this object is inexpensive and durable and ma be applied to systems now in use, althougi it is eculiarly ada ted for that in connection wit which it is s own.

It will be apparent from the above description that the current mav be reduced to any desired fraction of the ful current by a proper adjustment of the relative resistances of coils 36 and 39, and by means of adjustable spring 3l this reduction may take place at any desired potential of the battery.

As many changes could be made in the and many apparently widely different embodiments of my invention could be made without departing from the scope thereof, I intend that all matter contained in the above description and about core 27 shown in the accompanying drawing shall be interpreted as illustrative and not in a i sense.

n desire it also to be understood that the language used in the following claims is inlimit- E tended to cover all' of the features of the invention herein described' and all statements of the scope of the invention which as a matter of language might be said to falltherebetween.

. That I claim as my invention, and desire to secure by Letters Patent, is-

l. In combination, a enerator, an external circuit' leading two paths inparallel and means a upon the voltage of said generator exccedi 0 a certain point to open-circuit one 'of salia paths and generator through the other path.

2; In combination, a enerator, an external circuit leading from t e samepomprising' two paths of unequal resistance connected in generic and specific' from t e saine com rising apte parallel, and means adapted upon the voltage of said generator exceedln a certain omt to open-circuit the path' avii the east resistance and divert the externa output of the generator through the other path.

3. In combination,-Y for the same comprising two aths connected in parallel, means -controlla by the current in one of said paths adapted to maintain the a generator, a circuit current therein substantially constant andmeans whereby upon the voltage of sai gen-f erator exceeding a certain point the other of said paths is cut out.

'4. In combination, a generator, arcircuit for the same comprising resistance connected in parallel, means controlled by the current in one of said paths adapted to maintain ythe current therein substantially constant, and means whereby upon the voltage of said enerator exceedingl a certain point the pati of less resistance is cut out. A t 5. In combination, a generator,` a circuit for the same comprising a plurality of paths connected in parallel, means controlled by two paths of unequal los the current in one of said paths adapted to maintain the current therein substantiall constant, and means whereby upon the vo tage of said generator exceeding a certain polntIanother of said paths will be cut out.

G. for the same comprising a secondary battery having serially connected therewith two elec-4 trical conductors connected in parallel and means whereby upon the voltage of said generatorI exceeding a certain point one of said conductors is opened and the current to said battery diverted through the other conductor.

7. In combination fa for the same hairingtherem a secondary battel-y, a portion of said circuit comprising two aths connected in parallel, means controlled y the current in one o f said paths adaptedto constant, and means whereby upon the vo tage of said generator exceeding a certain point one of said paths 1s opened and the curmaintainthe current therein substantial] n combinationI a generator, a circuit IIS generator, a circuit A rent to said battery diverted through the other ath.

8. n combination,a gener-alena variableresistance medium serially connected in the field ofsaid generator, a circuit for snid generator comprisin f a solenoid ade ted to controlthe resistance of said mariah .resistance medium; a shunt about said solenoid, and means controlled by the volta-ge of said gcneretor whereby upon said voltage exceeding: a4 certain rpoint soif shunt is opened.

9. In combination, n generator, a variableresistencedevice adapted to control the resistance of the field o seid generator-,ascienoid' connected in the circuit of' seid generator adapted to-control said variable-resistance devxceso -as to -maintn-in constant acurrent through said solenoid, e. shunt about said solenoid, and'mcans controlled by the voltage of said generator whereby upon seid v'oltage exceeding'a certain point said shunt is opened.

10. In combination, a generator', a highlresistnnce circuit bridged across the terminels of saidgenorator', two switches, a mein circ-uit' com rising two' p ths connected in parallel an s. plurality Vo electronm-gnetic means serially connected iinsaid first-mentioned circuit controlling said switches, one of s aid switches controlling sairlrsecond-mentioned circuit und the other cont olling one of said paths. i:

1l. In'combinn.t.ion, a gener tor, a highresistance circuitl bridged acroshleiermi- ,"s` main nals of scid'generator, two switch l of pat-lisboncircuit comprisinga pluralit' neet-ed iu parallel and e. urality of lectromngnetic means seriell)J connected in said first-mentioned circuit controlling said switches, one of said switches con trolling said second-mentioned'circuit and the other controllincr' one of seid paths.

l2. n combination, a. generator, a-highresist-ence circuit bridged across the terminale of said generator, two switches, a moin circuit comprising two piths connected in parallel, means controlled by the current in one of said paths adapted to maintain the current therein substantially constant, and a plurality of' electromagr rcfcenns serially connected in said first-n-` .tio' circuitcontrolling said switches, one of said switches controllin seid second-mentioned circuit and thc otier controlling one of Suid paths.

13. In combination, n generutor, a highrcsistance circuit bridged across the terminels of said generator, two switches, a main circuit comprising two paths of unequal resistancc connected in parallel und a storage battery, means cont-rolled by the current in one of said paths adapted to maintain the current therein substantially constant, and a plurality of electromagnetic means serially caisse connected in said tiret-mentioned circuit controlling seid switches, one of said switches contrcllinvssid second-mentioned circuit and the orner controlling one of sa icl 4p tits.

14. In combination, u. generator, a` highresistsnce circuit' bridged across the terminais of said generator, e main circuit comprising two aths connected in parallel and a secondery attery, means in ons of scid eths ad opted to control the field strength o said gener-eter and maintain' the current in seid path substantially constant and two rungnetic switches the coils of .vnieh are serially connected in snid.first-mentioned circuit on'e of which controls said second-inentione circuit nnd the other ol which controls one of said paths and is adapted to cut out said path upon the voltage of seid generator exceeding a certain point. A

15. A secondary batt-ery, s plurality of conductors carrying current to said secondary battery, menus ade ted upon the voltage of said battery reaching' c predetermined point to open-circuit one of seid conductors, and m'enns `adopted automatically to'maintain the current in the other of said conductorsl substantially constant.

16. In combination, a generator, e. highresistance circuit bridged across the terminals of said generator, a mein circuit comprisin two paths connected in parallel and a secon ary battery, incans'iu one of scid paths adapted to control the licld strength'of snid generator end maintain the current in said putin substantially constant, and two mn netic switches the c'oils of which ure serielly connected in said first-mentioned circuit, one of which controls said second-mentioned circuit and the other of which is controlled by the vfoltsge of said generator and is adapted to cut out, one of sold paths upon the charge of seid battery exceeding n. certain point.

17. In combination, a generator, a. highresisteuce circuit bridged across the terminals of. seid generator, a mein circuit comprisino' tvo paths of unequal resistance connecte Ln parallel und n storage. battery means controlled by the current in one o said paths adapted te maintain the current therein substantially constant, and two magnetic switches the coils of which :are serial y connected in said first-mentioned circuit, one

of which controls said second-mentioned cir- IOC IXO

cuit and the other of which is controlled by the voltage of said tgenerator and is adapted upon the charge o said battery reaching a. certain point to cut out one of said paths.

In testimony whereof I aflix my signature inthe presence of two witnesses.

- l'l/'ILLIAM I. THOMSON.

i'itnesses:

J. B. KNOX, ROBERT S. BLAIR. 

